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Both a 2010 C207 E350 and a W212 E350 4matic as well as a W203 C180 kompressor Sport Coupe
2010 E350 Coupe M272 timing chains and tensioner
Hello to the forum, brand new here with a relatively serious issue.
A year and a half ago I imported a US spec (I live in Bulgaria) E350 C207 with the M272 engine and in the last 4000km (2500 miles) I am getting a chain rattle on cold startups. I got it at 132000km (82k miles) and is currently at 162k km (100k miles). Oil has been changed every 8-10k km (5-6.2k miles) with the OEM oil. On my previos service I by mistake ordered the OEM 5w30 oil instead of the 5w40 I usually run. I figured that it wouldn't be an issue since it is a option to run it and it was the winter/ spring season. Nearing my service interval is when the rattling started. I have since switched back to the 5w40 oil I was running hoping that was the cause but alas the rattle persists.
I have read on here that the M272 has had numerous cases of tensioners failing. How likely is it for the tensioner to fail or did I ruin my chain by running thinner oil? I have no timing DTCs and the rattle is only at cold startups. Has anyone attempted to replace just the tensioner on the C207? How is acces to it and can it be done at home without lifts/ramps? Did I take too long to take action and usually how do the chains perform since to me 100k miles is not that much. I have read how to replace the chain without removing the heads but I really wish to not have to do it since I don't have the space to do it at home and it is a rather expensive job to be done at a shop.
Any help is greatly appreciated.
tldr: M272 chain rattle on cold startups at 100k miles. Possibility of a bad tensioner or a stretched chain?
They are check valves in the oil galleries designed to maintain oil pressure to the camshaft tensioner system. After switching the engine off, the check valves maintain oil in the tensioners. Loss of pressure causes the scraping sound you here as the tensioners allow the chains to move around etc.
There are threads on here on how to do that with pics. Unfortunately if left too long, the lack of pressure causes many issues including loss of pressure to the main oil galleries which can cause issues on the bottom end.
Get it checked out and repaired ASAP or you might be replacing an engine.
IMHO it is one of the dumbest things MB did for their engines. There was a huge recall over this for the v6 engines back in 2013-14 and MB redesigned the check valves to be more robust IIRC. Those are the "updated parts" I mentioned. MB put those in many models and all were affected. Sorry i dont have pics or a link to the threads but you should be able to find them easily on here.
Both a 2010 C207 E350 and a W212 E350 4matic as well as a W203 C180 kompressor Sport Coupe
Changed the chain tensioner and alas it was not it.
As I am currently going through the forum to look for info as far as I understand there are check valves for each valve lifter/ cap (?) and supposedly 2 in the oil galleries, 1 being under the oil cooler housing (?) and one on the oil pump (?) but I am completely unsure. I kind of rule out the valve ones since the rattle sounds erratic and less organised/ timed as it should be with lifters. What I'm seeing on the oil pump looks more like a pressure solenoid rather than a return valve and even if it is it seems unavailable where I live since its marked out. I can't find anything on parts schematics under the oil cooler housing. What I have read on here is people having issues with the No 72 O-ring aging / cracking and causing similar issues. Still looking for info since I dont't want to pull the oil pans more than once.
#55 in the pic is the oil pressure solenoid. it was designed to reduce pressure under ECu control at certain rpms,,like 1000 -3000 rpm. This was ONLY for helping increase the MPG of the car(s). Please see the huge oil control solenoid thread on here for more info on that.
I could see #72 being an issue but not intermittently. you would get low pressure all the time.
You may have to remove the oil pan to chase this down. If so then I would replace the oil control solenoid for sure while in there. FYI if the oil solenoid failed it fails in the high pressure mode. so unlikely the system is low pressure...it is far more likely to be the check valves for the camshaft tensioners.
Did you look for the threads on that?
You might try using an engine flush product added to the oil to see if that might help remove crud from the system..cheap but no gaurantee. Also you can try using heavier weight oil like 10w40 to test to see if that helps with the scraping and clatter.
BTW my 2012 E350 was scraping very loudly which I failed to address for 6 months. Whne I took it to MB for diagnosis, they told me it had lost pressure in the main oil galleries as well, requiring a full on engine rebuild, everything was replaced under my warranty including the check valves tensioners all bearings and oil control solenoid yada yada....If I was you i would get it addressed asap before you have a major engine issue like I had.
Here is a youtube video going over the issues including solenoids, camshaft issues and the rattle noise upon startup.
Both a 2010 C207 E350 and a W212 E350 4matic as well as a W203 C180 kompressor Sport Coupe
Originally Posted by WRC-LVR
#55 in the pic is the oil pressure solenoid. it was designed to reduce pressure under ECu control at certain rpms,,like 1000 -3000 rpm. This was ONLY for helping increase the MPG of the car(s). Please see the huge oil control solenoid thread on here for more info on that.
I could see #72 being an issue but not intermittently. you would get low pressure all the time.
You may have to remove the oil pan to chase this down. If so then I would replace the oil control solenoid for sure while in there. FYI if the oil solenoid failed it fails in the high pressure mode. so unlikely the system is low pressure...it is far more likely to be the check valves for the camshaft tensioners.
Did you look for the threads on that?
You might try using an engine flush product added to the oil to see if that might help remove crud from the system..cheap but no gaurantee. Also you can try using heavier weight oil like 10w40 to test to see if that helps with the scraping and clatter.
BTW my 2012 E350 was scraping very loudly which I failed to address for 6 months. Whne I took it to MB for diagnosis, they told me it had lost pressure in the main oil galleries as well, requiring a full on engine rebuild, everything was replaced under my warranty including the check valves tensioners all bearings and oil control solenoid yada yada....If I was you i would get it addressed asap before you have a major engine issue like I had.
Here is a youtube video going over the issues including solenoids, camshaft issues and the rattle noise upon startup.
Now I get where the misunderstanding was. Mine has the older M272 which is from 2003ish to 2011, the m276 is the new engine with direct injection from 2012. While both are 3,5l V6 the timing is completely different. On the M272 the chain passes only through the intake camshaft and it turns the exhaust camshaft through a set of gears. On the m276 the chain passes through both cams and has 2 chain tensioners rather than one. Inherently different engines even if derived from one another.
What's driving me insane is that the noise is clearly reliant on weather conditions. If it is cold outside during the 6-8 hours the car is parked the rattle does not appear while if parked under the summer sun and the car stays hot it rattles the most. Obviously the oil is draining from somewhere but for the life of me I cannot find it.
So specifically for the M272 the issues can stem freom
stretched timing chain
failed hydraulic timing chain tensioner due to lack of oil pressure or check valve failure
Balance shaft gears that are worn
worn cam adjuster
low oil level
loose heat sheilds
See this video for the M272 :
Here's a more detailed explanation:
Timing Chain and Tensioner:
The M272 engine uses a timing chain to synchronize the crankshaft and camshafts. The timing chain tensioner keeps the chain taut, preventing it from rattling or jumping.
Cold Start Noise:
When the engine is off, the oil pressure drops. The hydraulic timing chain tensioner can lose its tension, causing the chain to rattle against the guides and sprockets when the engine is started.
Potential Damage:
If the timing chain is not properly tensioned, it can skip a tooth on the camshaft sprockets, leading to incorrect valve timing and potential piston-to-valve contact.
Balance Shaft Issue:
A specific problem with the M272 engine is wear on the balance shaft gears, which can also cause rattling noises on startup.
Other Possible Causes:
While timing chain issues are the most common, other problems like worn cam adjusters, low oil levels, or even a loose heat shield can also contribute to rattling noises.
This video shows how to diagnose the balance shaft issue by spinning the engine:
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